The present invention relates to a speed trnsmission of the chain transfer type and adapted to be applied to bicycles, in particular sports bicycles.
As is known a speed transmission is presently used on bicycles for improving the bicycle efficiency, since it permits to fit the pedalling force to the road gradient.
Also known is the fact that such a speed transmission is absolutely necessary on racing bicycles and, in general, on sports bicycles.
Presently available bicycle transmissions, on the other hand, are affected by several operating drawbacks.
Some transmissions, for example, can be operated exclusively by complex operations, such as by carrying out some backward pedalling strokes or by excessively displacing operating levers and the like.